• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.636-643
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• 2006

Supercritical water oxidation of DMMP using continuous flow reactor was studied at temperature ranging from 440 to $540^{\circ}C$ and a fixed pressure of 242 bar. The range of residence times in the reactor was from 10 to 26 s, and oxygen excess value varied from -40 to 200%. Destruction efficiencies (DE) of DMMP were greater than 99.7% at $540^{\circ}C$, and increased as the DMMP concentrations were increased. DE of DMMP were significantly affected by oxygen concentration under stoichiometric amount, but showed little difference over stoichiometric amount. On the basis of 30 data with conversions greater than 85%, kinetic correlations for the DE of DMMP were developed. The pre-exponential factor was $(1.10{\pm}0.76){\times}10^6$, and the activation energy was $90.66{\pm}3.87kJ/mol$, and the reaction orders for DMMP and oxygen were $1.02{\pm}0.03$, $0.32{\pm}0.03$, respectively. The model predictions agreed well with the experimental data.

• Resources Recycling
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• v.30 no.6
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• pp.12-18
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• 2021

The water-gas shift reaction is the subsequent step using steam for hydrogen enrichment and H₂/CO ratio-controlled syngas from gasification. In this study, a water-gas shift reaction was performed using syngas from an RPF gasification system. The water-gas shift using a catalyst was performed in a laboratory-scale tube reactor with a high temperature shift (HTS) and a low temperature shift (LTS). The effects of the reaction temperature, steam/carbon ratio, and flow rate on H₂ production and CO conversion were investigated. The operating temperature was 250-400℃ for the HTS system and 190-220℃ for the LTS system. Steam/carbon ratios were between 1.5 and 3.5, and the composition of reactant was CO : 40 vol%, H₂ : 25 vol%, and CO₂ : 25 vol%. The CO conversion and H₂ production increased as the reaction temperature and steam/carbon ratio increased. The CO conversion and H₂ production decreased as the flow rate increased due to reduced retention time in the catalyst bed.

• Korean Journal of Head & Neck Oncology
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• v.18 no.2
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• pp.184-191
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• 2002

연구방법 : 근치적 목적의 동시항암방사선치료를 시행받은 비인강암 환자들을 대상으로하여 치료 효과와 독성에 대한 후향적 분석을 시행하였다. 환자 및 방법 : 1993년 8월부터 1999년 3월까지 원격전이가 없는 50명의 비인강암 환자들이 방사선 치료기간 중 주 1회의 시스플라틴 $20mg/m^2$을 투여받았고, 1999년 4월부터 2000년 4월까지 20명의 환자가 상기 용량의 시스플라틴에 더하여 경구용 UFT300mg을 추가적으로 투여받았다. 총 70명 환자들의 임상기록과 병리 기록지를 검토하였다. 결 과: 연령의 중앙값은 47세 (범위 $18{\sim}76$)였고, 남자와 여자가 각각 53명과 17명 이었으며, 병기 II, III, IVA, IVB가 각각 23명, 14명, 15명, 18명이었다. 치료에 대한 반응율은 92.8%(95% C.I. $42{\sim}143%$)였고(완전반응 57명, 부분반응 8명), 총 34개월의 추적 관찰 기간 동안에 완전반응을 보인 57명 중 21명에서 재발(국소재발 5, 원격전이 11, 복합전이 5)을 하였다. 3년 무진행 생존율은 51.5%였으며 5년 생존율은 60.3%였다. 경구용 UFT의 추가적 사용은 주 1회 시스플라틴 항암치료에 비하여 반응율과 생존율 및 독성에 유의한 영향을 미치지 않았다. 결 론: 주 1회 저용량 시스플라틴$\pm$경구용 UFT를 이용한 동시항암방사선요법은 비인강암 환자의 치료에 있어서 비교적 적은 독성으로 높은 반응율을 나타내었으나, 향후 재발율을 감소시키기 위한 연구가 지속되어야 할 것으로 사료된다.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.119-123
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• 2001

철 농도변화에 따른 대사산물 생성에 대한 반응은 중온조건에서 회분식 실험으로 수해하였다. 철의 농도가 40mg/$\ell$까지는 철 농도의 증가에 따라 수소생성율도 증가하였다. acetate 생성율은 철의 농도가 증가함에 따라 감소하였다. Butyrate, ethanol 및 butanol은 각각 철 농도가 200,200 및 400mg/$\ell$에서 최대 생성율을 나타내었다. 철의 농도가 200mg/$\ell$이상의 농도엘 때에 propionate, i-butyrate 및 valerate 생성율이 철의 농도가 200mg/$\ell$ 이하의 경우 보다 낮았다. 미생물농도의 경우 철 농도가 300mg/$\ell$까지는 농도가 증가함에 따라 미생물농도도 증가하였다.

• KSBB Journal
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• v.7 no.3
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• pp.179-185
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• 1992

An anion-charged membrane was used for selective retention of coenzyme NAD(H) in reactor without any chemical modification. The membrane could reject permeation of NAD (H) (80.9%) but not reject permeation of product. The retention ratio was enhanced in the presence of albumin and Tris-maleate buffer. A bioreactor equipped with a membrane, NTR 7410 was constructed and used in the repeated batch production of sorbitol. NADH-dependent sorbitol dehydrogenase from sheep liver was used for the production of sorbitol from fructose. The coenzyme oxidized was regenerated with alcohol dehydrogenase. 47g/L sorbitol was produced for 198 hr with a substrate conversion ratio of 70%. The retention ratio was almost maintained throughout the entire reaction.

• Journal of Energy Engineering
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• v.9 no.3
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• pp.228-236
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• 2000

본 연구에서는 순간 고온식 tubing-bomb reactor를 사용하여 41$0^{\circ}C$에서 Alaska산 아역청탄, 폐타이어, 폴리프로필렌 혼합물의 공동액화 시 액화특성 및 상승효과를 연구하였다. 석탄, 폐타이어와, 폴리프로필렌의 조성을 변화시키고 수소공여용매인 tetralin의 양을 변화시켜가며 공동액화를 진행했을 경우 공동액화율을 살펴보면, 무촉매 반응의 경우 폴리프로필렌의 양이 많아지면 tetralin이 첨가되지 않았을 경우 액화율이 증가하였으나 tetralin이 첨가되었을 경우 공동액화율이 감소하였다. 촉매 반응의 경우에는 모든 반응조건에서 상승효과가 나타났으며 폴리프로필렌의 양이 증가할수록 공동액화율이 증가하여 석탄 : 폐타이어 : 폴리프로필렌의 조성이 1:1:3에서 tetralin 4$m\ell$, Co-naphthenate 촉매 사용하였을 때가 최적의 반응조건으로 83%의 공동액화율을 나타내었다.

• Geophysics and Geophysical Exploration
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• v.23 no.2
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• pp.67-71
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• 2020

In this study, we derive closed-form expressions of magnetic gradient tensor due to a circular cylinder. Because the expression for magnetic field has been derived in a previously conducted study, expressions are developed for the magnetic gradient tensor based on the derivatives of the expressions of magnetic field with respect to the variables of the Cartesian coordinates. Furthermore, expressions are derived for the magnetic gradient tensor based on the relations between the Cartesian and cylindrical coordinates in the derivative because the expression for magnetic field contains variables of cylindrical coordinates owing to its axial symmetry.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2004.05a
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• pp.98-102
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• 2004

반도체 산업용 실리콘 잉곳의 절단공정에서 발생하는 폐슬러지 중에는 고순도의 실리콘이 함유되어 있으며, 이 슬러지로부터 분리, 회수한 Si로부터 실리콘화합물 합성하였다. 고비점의 potasium alkoxide 촉매 존재하에서 금속 실리콘과 에탄을 혹은 메탄올과 같은 알코올과의 고액반응에 의해 알콕시 실란을 합성할 수가 있었다 알콕시 실란을 합성반응속도는 반응온도에 크게 의존하였고 최적반응 온도는 $180^{\circ}C{\sim}195^{\circ}C$ 정도이었다. 촉매 첨가량에 따라 알콕시 실란의 반응율이 달라졌으며, 알콕시 실란의 반응율은 최고 90%로 높은 값을 나타내었다.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.641-647
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• 2005

The partial oxidation of methane is one of important processes for hydrogen production. As a membrane reactor, palladium-silver (Pd-Ag) alloy membrane prepared by electroless plating technique was employed for partial oxidation of methane. The experimental variables were reaction temperature, $O_2/CH_4$ mole ratio, $CH_4$ feed rate, and $N_2$ sweep gas flow rate. The methane conversions increased with the reaction temperatures in the range of 350 to $730^{\circ}C$. The highest methane conversion and CO selectivity were obtained at the condition of $O_2/CH_4$ mole ratio of 0.5 and $730^{\circ}C$ using commercially available nickel/alumina catalyst. The Pd-Ag membrane reactor showed higher methane conversions, 10~40% higher, compared to those in a traditional reactor.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.573-579
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• 1996

Effects of operating variables on the conversion of the formation reaction of meta boric acid from ortho boric acid in a laboratory-scale bubble column reactor were investigated to obtain the basic data which are indispensable for the design, scale-up, control, development and operation of industrial bubble column reactors. Reaction time and pressure, particle size of reactant and gas flow rate were chosen as experimental variables. Effects of the experimental variables on the gas holdup in the bubble column reactor were also discussed in relation to the conversion of reaction. From the results of this study, the optimum conditions were drawn as follows : Reaction time ; 35~40(min), reaction pressure ; 92~95(kPa), particle size ; under $0.6{\times}10^{-3}(m)$, gas flow rate ; 0.07~0.08(m/s).